Certain sedimentary features are very temporary; Bird tracks in sand; ripples formed by water flowing over sand; etc. The fact that such features are preserved in rock demonstrates the necessity of the rapid formation of sedimentary rock.

Ripple MarksUbiquitous Rippel Marks, Robert R. Shrock, Proff. of Geology, M.I.T., "Because they are one of the commonest and most widespread of original sedimentary features, they have been described and illustrated in countless reports. ...Ripple marks are preserved in conglomerates, sandstones, and siltstones, and in clastic limestones and dolostones. ...Many examples have been described from rocks of all ages..." SEQUENCE IN LAYERED ROCK, p.93, 95

"Rapid," Edwin D. McKee, "The chief significance of ripple lamination in the geologic record is that it is an indicator of environments involving large and rapid sand accumulation...areas where addition of new sand normally is at a slow rate, have little chance of developing into superimposed ripple lamination... In contrast, areas in which sand accumulates periodically but rapidly, as in river flood plains were sand laden waters of strong floods suddenly lose velocity are very favorable for building up ripple-laminated deposits." Primary Sedimentary Structures and Their Hydrodynamic Interpretation, Society of Economic Paleontologists & Mineralogists, p.107.

Once formed into rock these ephemeral features would erode rapidly if not covered and protected from erosion. Therefore, not only must these layers be formed rapidly, the subsequent layers must also be deposited very shortly thereafter.

Ripple marks are so common that it has been said, if any bedding plane is followed far enough, ripple marks will be seen. They are in virtually all kind of sedimentary rock.

The implication is that all kinds of sedimentary rock are formed rapidly and so did the layer above it and the one above it and so on. Once this picture develops in our minds, it becomes clear that we are not looking at isolated events separated by long periods of time but a rapid series of events.

Bird Tracks
Think about it. How long would bird tracks last in the mud? This rock formed before they disappeared!